Clinically, atrial fibrillation (AF) is one of the most common cardiac arrhythmia, and patients with arterial fibrillation carry high risk of stroke. Oral administration of anticoagulation such as warfarin for the prevention of stroke has some risks to induce bleeding; moreover, some patients are not able to tolerate the medication. Percutaneous occlusion of the left atrial appendage is safe and effective for the prevention of stroke in patients with atrial fibrillation, although at present it is only used for the patients who have contraindications to anticoagulation medication. This paper aims to review a variety of left atrial appendage occlusion devices and to analyze the relationship between the different shape design of occluder and the left atrial appendage morphology.

Objective To explore the method and technique to gain adequate seed cells for cartilage tissue engineering Methods hTERT gene was introduced into rabbit mandibular condylar chondrocytes by eukaryotic vector Rapidly proliferated immortalized chondrocytes in positive clones in micro carrier rotary cell culture system (RCCS) were screened and selected The growth of immortalized chondrocytes and the metabolic rate were observed Collagen type Ⅱ expression of immortalized chondrocytes of the experimental groups was observed The immunohistochemical results were compared with those of the control groups Results The immortalized chondrocytes in experimental groups could grow rapidly with a high metabolic rate and shorter population doubling time (PD) ( P

Objective:To investigate the effects of two SNP sites of delta-like ligand protein-1 (DLL1) gene rs2738822 (C>T) and rs9459988 (T>G) and gene expression on bone marrow suppression after neoadjuvant chemotherapy for breast cancer.Methods:Breast cancer patients who received neoadjuvant chemotherapy were selected as study subjects, including 90 patients with severe bone marrow suppression and 72 patients with mild bone marrow suppression. Patient’s demographic characteristics and laboratory test indicators were collected. Two SNP sites of DLL1, rs2738822 and rs9459988, were genotyped by capillary electrophoresis and section analysis (SNaPshot) . The relative mRNA expression of DLL1 gene was detected by quantitative reverse polymerase chain reaction (QRT-PCR) method.Results:For The rs2738822 of DLL1 gene, the genotype distribution difference between severe and mild bone marrow suppression groups was statistically significant ( χ2=8.622, P=0.013) . Compared with CC genotype, CT and TT genotype carriers had a higher risk of severe bone marrow suppression, with an OR value of 2.746 (1.335-6.882) and 3.054 (1.282-8.143) , respectively. The dominant model results showed that TT OR CT carriers had a significantly higher risk of severe bone marrow suppression than THOSE with CC genotype [ OR=2.976 (1.231-4.963) ]. For rs9459988, there was no significant difference in genotype distribution between severe bone marrow suppression group and mild bone marrow suppression group ( χ2=2.149, P=0.342) . Results of the dominant model showed that TG or GG carriers had a significantly higher risk of severe bone marrow suppression than TT carriers, with an OR value of 2.046 (1.053-5.611) . The relative mRNA expression level of DLL1 gene was 1.15±0.23 in patients with severe bone marrow suppression, which was significantly lower than that in patients with mild bone marrow suppression (2.64±0.51) ( t=6.381, P<0.001) . For rs2738822, with the increase of T allele, the relative mRNA expression level of DLL1 gene decreased gradually ( P<0.05) . For rs9459988, the relative mRNA expression level of DLL1 gene in patients with mutant allele G was also significantly lower than that in wild-type CC carriers ( P<0.05) . Conclusion:Mutations of DLL1 genes rs2738822 and rs9459988 are related to the occurrence of severe bone marrow suppression after neoadjuvant chemotherapy for breast cancer, and can be used as a genetic marker to predict the degree of bone marrow suppression after neoadjuvant chemotherapy for breast cancer patients.

ObjectiveTo evaluate the clinical effectiveness of posterolateral autograft bone graft fusion transpedicular screw system internal fixation and anterior debridement in the treatment of dorsal and lumber spinal tuberculosis. MethodsFrom March 1996 to July 2000,posterolateral autograft bone graft fusion transpedicular screw system internal fixation and anterior debridement procedures were used in 62 patients suffering from dorsal and lumber spinal tuberculosis in our department,48 of them were involved in a longitudinal study follow-up for a mean of 3.6(1.5-5.5)years postoperatively. ResultsAll patients showed successful posterolateral bone graft fusion. Among 38 cases of Pott's paraplegia, 30 were completely recovered,5 were partly recovered,the rate of recovery was 92.1%. The average immediate postoperative correction of kyphosis angle was 29.1°,the average loss of correction was only 3.2°at final follow-up.ConclusionsPosterolateral autograft bone graft fusion transpedicular screw system internal fixation and anterior debridement procedure were found helpful in strengthening the stability of the spine in dorsal and lumber spinal tuberculosis, providing successful interbody fusion and recovery of Pott's paraplegia, correcting the kyphosis, and preventing progression of kyphosis.

In recent years, clear aligner technology has been maturing and is rapidly gaining popularity in the orthodontic market for its aesthetic and removable properties. However, despite the background of its large-scale clinical application, mechanical properties of clear aligners need to be studied in depth. This paper reviews the factors influencing mechanical properties of clear aligners and the current status of research to provide evidence-based guidance for clinical application.

Objective:To investigate the expression of miR-211-5p in peripheral blood of patients with myelosuppression after neoadjuvant chemotherapy for breast cancer and its effect on Notch signaling pathway by targeting cyclooxygenase 2 (COX2) gene Regulation mechanism.Methods:From Jan. 2018 to Jan. 2021, 185 breast cancer patients who received neoadjuvant chemotherapy in Linyi People’s Hospital for the first time were included as the research objects. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the mRNA expression levels of miR-211-5p, COX2 gene and Notch signaling pathway related genes (Notch1, Jagged1 and Hes1) . The miR-211-5p mimic, inhibitor, mimic NC, and inhibitor NC were transfected into SD rat bone marrow mesenchymal stem cells, and the mRNA expression of miR-10a-3p and COX2 genes was detected by qRT-PCR for 48 hours. Western blot method was used to detect the protein expression levels of Notch signaling pathway related genes.Results:The relative expression of miR-211-5p in patients with severe myelosuppression was 2.41±0.32, which was significantly higher than that in patients with mild myelosuppression (1.53±0.18) ( t=6.385, P<0.001) ; The relative expression of COX2 gene mRNA in patients with severe myelosuppression was 3.64±0.74, which was significantly lower than that in patients with mild myelosuppression (5.37±1.02) ( t=7.469, P<0.001) . In patients with severe myelosuppression, there was a significant negative correlation between miR-211-5p and COX2 gene mRNA levels ( r=-0.694, P=0.006) . The results of the dual luciferase report experiment confirmed that COX2 was the target gene of miR-211-5p. The relative expression of Notch1, Jagged1, and Hes1 mRNA in peripheral blood of patients with severe myelosuppression were 2.35±0.41, 2.76±0.46 and 3.04±0.52, respectively, which were significantly lower than those in patients with mild myelosuppression (4.12±0.63, 4.53±0.58 and 5.12±0.67) ( t=5.367, 6.114 and 6.135, respectively, P<0.001) . After transfecting SD rat bone marrow mesenchymal stem cells with miR-211-5p mimics and inhibitors, the relative expression of miR-211-5p in the mimic group was 3.46±0.49, significantly higher than that in the mimic NC group (2.24±0.32) The relative expression of miR-211-5p in the inhibitor group was (1.28±0.19) and (2.33±0.37) inhibitor NC group ( P<0.001) , while the relative expression of miR-211-5p in the inhibitor group was significantly lower than that in the other three groups ( P<0.001) . The mRNA expression of COX2 gene in mimic group was 2.73±0.36, which was significantly lower than that in mimic NC group (4.05±0.59) , inhibitor group (6.15±0.86) and inhibitor NC group (4.18±0.65) ( P<0.001) , while mRNA expression of COX2 gene in the inhibitor group was significantly higher than that in the other three groups ( P<0.001) . The expression of Notch1, Jagged1, and Hes1 in the inhibitor group was significantly increased, while the expression of Notch1, Jagged1, and Hes1 in the mimic group was significantly decreased. Conclusion:The expression level of miR-211-5p in peripheral blood of severe myelosuppressed patients with breast cancer after neoadjuvant chemotherapy is significantly increased, and the Notch signaling pathway can be inhibited by targeted down-regulation of COX2 gene expression.

Objective To evaluate the feasibility and safety of a delivery pathway for the performance of percutaneous left atrial appendage (LAA) occlusion in experimental canine models. Methods Transseptal puncture was performed via femoral vein approach under fluoroscopic and angiographic guidance in 12 experimental dogs. A pigtail catheter was advanced into the left atrium (LA), which was followed by LA angiography. The diameters of the neck of LAA were measured on LAA angiogram obtained in appropriate projection. After the delivery sheath was advanced along the wire into LA, a pigtail catheter was inserted into the ostium of the LAA and the sheath was then advanced over the pigtail into the LAA. LAA angiography was then performed through the delivery sheath to confirm the position of the delivery sheath. One hour after the procedure both electrocardiography (ECG) and transthoracic echocardiography (TTE) were carried out in five dogs to check the results, immediately after which the five dogs were sacrificed to macroscopically observe the damages of the puncture site of inter-atrial septum as well as inside the LA and LAA. One hour and 2 weeks after the procedure TTE was conducted in the remaining 7 dogs and these dogs were followed up for one month. Results One dog died of pericardial tamponade during the operation. In 8 dogs the LAA was clearly displayed in the projection position of right anterior oblique (RAO) 30°/cranial (CRA) 20°,while in 3 dogs the LAA was well visualized in the projection position of RAO 30° , and in one dog in the projection position of RAO 30°/caudal (CAU) 20°. The diameter of LAA neck was (13.6 ± 5.2) mm. The delivery sheath was safely advanced into the LAA along the pigtail catheter in all dogs, and no air embolism, thrombus or pericardial tamponade occurred. Hematoma at puncture point of groin occurred in 2 dogs, which was absorbed through pressure dressing. Macroscopic examination of the heart performed immediately after the operation showed that no bloody pericardial effusion was found, and mild hematoma at posterior wall of LA was seen in one dog and mild damage of the upper-margin intima of LAA was noted in 2 dogs. The mean fluoroscopy time was (10.1 ± 2.5) minutes and the mean operation time was (58 ± 12) minutes. TEE showed no pericardial effusion 2 weeks after the procedure. During the follow-up period of one month no sudden death, stroke or infection occurred. Conclusion This method of placing the delivery sheath into the LAA is clinically safe and effective, and it can reliably establish a pathway to advance the LAA occluder into LAA.

BACKGROUND:The reciprocal force generated by the molar distalization with clear aligners can lead to anchorage loss.The effect of arch shapes and missing second premolars on anchorage has not been reported. OBJECTIVE:To analyze the effect of arch shapes and missing second premolars on anchorage during molar distalization with clear aligners using the finite element method. METHODS:Cone-beam CT data from an adult male were acquired from the database to establish the maxilla-upper dentition-periodontium-rectangular attachment-clear aligner model.The distal movement amount designed on the bilateral second molars was set to 0.25 mm.First,there were two groups in the study:second premolar bilateral presence and absence groups.Then,four subgroups in each group were created:tapered arch,ovoid arch,square Class Ⅱ Division 1 arch,and Class Ⅱ Division 2 arch groups.The Ansys software was used to calculate the displacement of the anchorage tooth and the stress of the periodontal ligament. RESULTS AND CONCLUSION:Mesial tipping and extrusion of first molars and premolars,labial inclination and intrusion of anterior teeth occurred during the upper second molar distalization with clear aligners.When the bilateral second premolars were missing,the mesial displacement of first molars increased significantly while that of first premolars and anterior teeth decreased in all groups.The square Class Ⅱ Division 1 arch group showed the least anterior labial inclination,while the tapered arch group showed the most.There was no significant difference between the ovoid arch group and the tapered arch group.Moreover,the magnitude of tipping in the square Class Ⅱ Division 2 arch group was slightly higher than that in the Class Ⅱ Division 1 arch group.The stress of the periodontal ligament of the anchorage teeth was concentrated on the cervical and apical regions of the teeth.And the lowest stress level was detected in the square arch group.Compared with the other groups,the stress on the labial cervical area of the periodontal ligaments was also significantly relieved in the square arch group.To conclude,the square arch is more favorable in terms of anterior anchorage control and periodontal ligament stress distribution.Anterior labial inclination efficiency can be increased in cases of Class Ⅱ Division 2 by designing the anterior labial inclination in conjunction with molar distalization.If the second premolar is missing during molar distalization,it is not conducive to opening up the space in the area of the missing tooth.

BACKGROUND:The thin alveolar bone in the lower anterior region increases the risk of labial bone resorption when intruding the teeth with clear aligners.The effect of sagittal overcorrection design on the labiolingual control of mandibular anterior teeth intrusion has not been fully investigated. OBJECTIVE:To explore the effect of overcorrection on the changes in the displacement and stress of the mandibular anterior teeth,especially the cervical and apical regions. METHODS:Through a male volunteer cone-beam CT data,the three-dimensional reconstruction of the mandible and teeth was conducted in the MIMICS and GEOMAGIC software.Moreover,the models of periodontal ligaments,attachments,and appliances were created in the SOLIDWORKS software.First,the study was divided into canine intrusion group and incisor intrusion group.Then,the overcorrection(0°,1°,2°)was designed on the bilateral mandibular central and lateral incisors.A total of six models were established.The models were assembled and imported into the ANSYS software to analyze and calculate the displacement and stress level. RESULTS AND CONCLUSION:(1)In the canine intrusion group,canines intruded and tipped lingually while incisors extruded and tipped lingually.In the incisor intrusion group,canines extruded and tipped lingually while incisors intruded and tipped lingually.(2)Without overcorrection,the incisors necks moved lingually while apexes moved labially.With overcorrection,the incisors tended to be upright,followed by labial tilt.The least cervical and apical displacements were detected under 1° overcorrection.(3)With overcorrection,the incisal cervical stress concentration area shifted from labial to lingual in the canine intrusion group,whereas the stress concentration area shifted from lingual to labial in the incisor intrusion group.(4)The incisors tended to tilt lingually when intruding the mandibular anterior teeth with clear aligners.The sagittal overcorrection design was conductive to maintain the stable position of incisors.However,the amount of overcorrection should be moderate.Excessive overcorrection might increase the labial inclination tendencies of incisors.

BACKGROUND:Sema3A is a power secretory osteoprotective factor.However,studies about Sema3A-modified dental pulp stem cells(Sema3A-DPSCs)are rare. OBJECTIVE:To explore the osteogenic differentiation ability of Sema3A-DPSCs and their regulatory effect on the osteogenic differentiation of the pre-osteoblast cell line MC3T3-E1. METHODS:First,Sema3A-DPSCs were constructed using a lentivirus infection system carrying the Sema3A gene.Control lentivirus-treated DPSCs(Vector-DPSCs)were used as controls.Sema3A-DPSCs or Vector-DPSCs were co-cultured with proosteoblast line MC3T3-E1 at the ratio of 1∶1 and 1∶3 for 24 hours.Finally,the Sema3A-DPSCs,Vector-DPSCs and their co-cultured cells with MC3T3-E1 were cultured for osteogenic induction and differentiation.Osteogenic gene expression was detected by alkaline phosphatase staining,alizarin red staining and real-time quantitative RT-PCR to evaluate osteogenic differentiation ability. RESULTS AND CONCLUSION:(1)Sema3A mRNA and protein expression levels in Sema3A-DPSCs were significantly up-regulated.The level of secreted Sema3A in cell supernatant was up-regulated.(2)Compared with the Vector-DPSCs,mRNA expressions of osteogenic genes alkaline phosphatase,Runt-related transcription factor 2,osteocalcin and Sp7 transcription factors in Sema3A-DPSCs were up-regulated;the activity of alkaline phosphatase was enhanced,and the formation of mineralized nodules increased.(3)There were no obvious differences in proliferation between Sema3A-DPSCs and Vector-DPSCs.(4)Compared with MC3T3-E1/Vector-DPSCs co-culture system,the expression of MC3T3-E1 osteogenic genes was up-regulated,and the total alkaline phosphatase activity was enhanced and more mineralized nodules were formed in the MC3T3-E1/Sema3A-DPSCs co-culture system.(5)The results suggest that overexpression of Sema3A can enhance the osteogenic differentiation of DPSCs.Overexpression of Sema3A in DPSCs can promote osteogenic differentiation of MC3T3-E1 in the DPSCs/MC3T3-E1 co-culture system.